Plaque for x-ray machines



June 13, 3939. 5 BUCKLEY 2,162,420

PLAQUE FOR X-RAY MACHINES Filed Aug 10, 1958 INVENTOR ATTORNEY PatentedJune 13, 1939 UNHTED STATS Timothy 5. Buckley, Jackson Heights, LongIsland, N. Y.

Application August 10, 1938, Serial No. 224,107

4 Claims.

This invention relates to a removable identification plaque for markingan X-ray negative and to the method of producing the same.

In Patent No, 2,120,064 of June '7, 1938, granted 5 to me is disclosedan identification plaque composed of a backing member, an intermediatelayer of plastic material and a covering member in the form of sheetmaterial, the intermediate layer being impermeable and the other membersbeing 19 permeable to X-rays. When the covering of the plaque issubjected to a scribing pressure, depressions are formed therein and theplastic material is displaced laterally with respect to the depressions,thus rendering the plaque permeable 15 to X-rays in said depressions.Plaques of the above character have been extensively and successfullyused but difiiculty is sometimes experienced if the scribing is donecarelessly, i. e. when insufi'icient pressure is applied, and thisdiffi- 20 culty is increased when the cover sheet is unduly thickbecause the depressions then may not be sufliciently deep which mayleave too much of the plastic impermeable material beneath saiddepressions.

25 The main object and feature of this invention is to overcome thesedifficulties.

In the accompanying drawing the invention is disclosed in a concrete andpreferred form, in which 30 Fig. 1 is a face view of a plaque embodyingthe invention with the several layers partly removed; and

Fig. 2 is a sectional view substantially on the plane of line 22 of Fig.l.

35 l indicates a backing member of any suitable material that ispermeable to X-rays such as glass. Upon this backing member is depositeda layer of plastic material 2 that is impermeable to X-rays. I havefound a composition com- 40 posed of white lead ninety percent,glycerine nine and one-half percent and a Japanned drier onehalf of onepercent to be suitable for my purpose. The percentages given areapproximate and are by weight and not by volume. I then 5 dust the layerwith a metallic powder 3 that is permeable to X-rays, preferablyaluminum powder. This powder forms a thin film or sheet as a protectivecovering over the intermediate layer and any surplus powder is removedas by blow- 50 ing it off. The edges of the plaque are then painted withordinary paint.

When the covering member is now subjected to scribing pressure by meansof a stylus, such as a pencil, said stylus will penetrate the coveringmember and the plastic layer substantially throughout the entire depthof the latter until said stylus contacts the backing member. In creatingthis furrow or valley 4 it is found that the covering member crumblesand, with the displaced plastic material forms lands or hills 5 adjacenteach side of the furrow, and that the lands or hills so formed do nothave any tendency to return into the furrow. A sharp negative of theinscription can therefore be produced,

The plaque, before being inscribed, will retain its characteristicspractically indefinitely.

The picture made by X-rays is referred to herein for convenience as anegative, but the term is not intended to be restrictive, as theinvention applies equally to any type of picture made by penetrativerays according to this invention.

I claim:

1. A removable identification plaque for marking an X-ray negativecomprising: a backing member permeable to X-rays, an intermediate layerof plastic material impermeable to X-rays, and a powder permeable toX-rays covering the plastic material, said powder crumbling and beingdisplaced with the plastic material when subjected to scribing pressureto form a furrow with adjacent hills.

2. A removable identification plaque for marking an X-ray negativecomprising: a backing member permeable to X-rays, an intermediate layerof plastic material impermeable to X-rays, and aluminum powder coveringthe plastic material.

3. The method of producing an identification plaque for marking an X-raynegative, which consists in depositing, on a backing member permeable toX-rays, a plastic material impermeable to X-rays, and dusting theplastic material with a metallic powder that is permeable to X-rays.

4. The method of producing an identification plaque for marking an X-raynegative, which consists in depositing, on a backing member permeable toX-rays, a plastic material impermeable to X-rays, and dusting theplastic material with aluminum powder.

TIMOTHY S. BUCKLEY.

